PELVIS MINOR 459 



cause its distension, and predispose to the formation of 

 haemorrhoids. 



Vena Hypogastrica (O.T. Internal Iliac Vein). Each 

 hypogastric vein is a large venous trunk which lies behind the 

 corresponding hypogastric artery. Its tributaries correspond 

 to the branches of the hypogastric artery, except that the ilio- 

 lumbar vein opens into the common iliac vein. 



The Lymph Vessels of the Pelvis Minor. It is only in rare 

 circumstances that the dissector will be able to display any of 

 the pelvic lymph vessels, but in favourable subjects he will be 

 able to localise some of the pelvic lymph glands. The main 

 groups of lymph glands of the pelvis are (i) the hypogastric 

 glands } (2) the sacral glands ; and (3) the rectal glands. - The 

 hypogastric glands are situated orr.fche side walls of the pelvis, 

 near the origins of the branches of the hypogastric arteries. 

 They receive lymph vessels from the membranous part of the 

 urethra, the lower part of the bladder, the prostate, the 

 upper part of the anal canal, and the lower part of the 

 rectum. Their efferent vessels pass to glands situated 

 round the common iliac arteries. The sacral glands lie along 

 the medial sides of the anterior sacral foramina. They 

 receive lymph vessels from the adjacent bones and ligaments, 

 from the rectal glands, and from the prostate. Their efferent 

 vessels end in the common iliac glands. The rectal glands, 

 four or five in number, lie in relation with the superior 

 haemorrhoidal vein and its two main tributaries. They 

 receive lymph from the rectum, and their efferent vessels 

 terminate in the lateral sacral glands. 



Dissection. As soon as the examination of the pelvic vessels 

 is completed the viscera should be drawn as far as possible from 

 the side wall of the pelvis, and any vessels which tend to prevent 

 the movement should be divided ; then the pelvic diaphragm 

 should be examined. It is composed of two muscles on each 

 side, viz. the levator ani and the coccygeus. Both the muscles 

 must be cleaned, and whilst that is being done care must be 

 taken to avoid injuring the fifth sacral and the coccygeal nerves 

 as they pierce the coccygeus near the coccyx. 



Mm. Levatores Ani. The two levatores ani muscles are 

 strong sheets of muscle fibres, which form the anterior and 

 greater part of the pelvic diaphragm. Each has a triple 

 origin. The anterior fibres arise from the back of the pubic 

 bone, between the attachments of the visceral and parietal 

 layers of the endo- pelvic fascia; the posterior fibres arise 



